public class SimpleCalcExtension {
    SimpleCalcController controller;

    public SimpleCalcExtension(SimpleCalcController cont) {
        this.controller = cont;
    }
   
    public PageReference div() {
        controller.result = controller.number1 / controller.number2;
        return null;
    }


    public PageReference mul() {
        controller.result = controller.number1 * controller.number2;
        return null;
    }


    public PageReference sub() {
        controller.result = controller.number1 - controller.number2;
        return null;
    }


    public PageReference add() {
        controller.result = controller.number1 + controller.number2;
        return null;
    }

}